Day Note Stopped Working

[AC Question]

Why did my Day Note on my Samsung Galaxy 10.1 Note 2014 edition just all of a sudden turn blue and now will not let me write anything on it? I turn it off in settings and then shut down then go back in and turn it back on and try it still the same, what is going on? It worked one day and not the next can anyone help? And it does work with this tablet if you are one of the lucky ones my friend has the same tablet and it never gave her trouble we didn't do anything different though...